Control circuits



May 8, 1934. P. H. CRAGO ET AL 1,958,161

CONTROL CIRCUITS Filed March 31, 1933 1-8 Operating Czrcaz'w. 26

INVENTORS Paul H. fiago and By Millard lzorezzield THEIR ATTORNE";

Patented May 8 1934 UNlTED STATES PATENT OFFICE CONTROL CIRCUITS of Pennsylvania Application March 31,

11 Claims.

Our invention relates to control circuits, and particularly to control circuits providing polarized control.

A feature of our invention is the provision of an improved and reliable control circuit for serially governing a plurality of relays, which may or may not be centrally located, from a relatively low voltage current source. A further feature of our invention is the provision of an improved and reliable control circuit for obtaining polarized control by energizing a polar relay only at reversals of polarity of the current. Still another feature of our invention is the provision of novel and improved means wherewith agreement between the position of a polar relay and the polarity of the controlling circuit is checked. Still other features of our invention will appear as the specification progresses.

We will describe one form of apparatus embodying our invention, and will then point out the novel features thereof in claims.

Referring to the accompanying drawing, the reference characters 2 and 3 designate a pair of conductors, such, for example, as a pair of line wires, which are reversibly connected with a and 3 are supplied with current of the reverse polarity from the battery 4.

Two controlling relays are governed by the current supplied to the conductors 2 and 3, the windings of the relays being arranged in such a manner as to be serially connected in the circuit, with a full-wave rectifier short-circuiting the windingof one or the other of the relays in a manner to appear later in the description. The reference character 7 designates a polar relay, the winding of which is arranged with one terminal connected with the conductor 3, and its other terminal connected with a conductor 3 leading to a terminal of the winding of a neutral relay 8, the opposite terminal of whose winding is connected with the conductor 2. It is clear, therefore, that the polar relay 7 and the neutral relay 8 have their windings connected in series with the control circuit including the conductors 2 and 3. The polar relay '7 is preferably of the type in which its polar armatures 18 and 20 re- 1933, SeriaI No. 663,765

main, when the relay is deenergized, firmly held in the position to which they were moved when the relay was last energized. The neutral relay 8 is a standard direct current neutral relay of any one of the several well known types. It is to be noted that the neutral relay 8 may equally as well be made a direct current polarized relax should it be found desirable to do so.

The reference character 9 indicates a fullwave rectifier comprising four asymmetrical units 21, 22, 23 and 24 joined in the customary full wave arrangement. Terminal 10 of rectifier 9 is connected with the conductor 3 by a wire 12, and an opposite terminal 11 is connected with the conductor 2 by a wire 13. Terminal 14 of the rectifier 9 is connected to a normal or left-hand contact 16 of the polar armature 18 of relay 7, and terminal is connected to the reverse or right-hand contact 17 of the armature 18, the armature 18 being connected with the conductor 3 by a wire 19.

The asymmetrical units 21, 22, 23 and 24 may be any one of several types adapted to readily pass current in one direction and to substantially block the flow of current in the opposite direction. A preferred form for these asymmetrical units, however, is that of the well known commercial copper oxide rectifier.

Relays '7 and 8 may be used to control any desired operating circuit either jointly or separately as the case may demand. Such operating circuits form no part of our invention, and are omitted from the drawingfor the sake of simplicity. It is deemed sufficient for the present description to disclose the polar armature of relay 7 and the neutral armatures 25 and 26 of relay 8 as being included in fragments of such circuits.

Assuming that the current supplied to the conductors 2 and 3 under the normal position of the controller contacts 5 and 6, that is, the position indicated by the solid lines in the drawing, is of normal polarity; and that the polar relay 7 has been energized in a manner to later appear, to move its polar armatures 18 and 20 to the corresponding normal position, that is, to the lefthand position as indicated in the drawing, the winding of the relay 7 is short-circuited through the rectifier 9 and the winding of the relay 8 is in circuit taking current from the conductors 2 and 3. This short-circuiting path around the winding of relay 7 extends from the conductor 3 over wire 12, terminal 10, asymmetrical unit 21 in its low resistance direction, terminal 14, normal contact 16 of relay '7, polar armature l8, and. wire 19 to the conductor 3 The circuit for energizing the neutral relay 8 under this normal condition can be traced from the positive terminal of battery 4 over controller contact 6, conductor 3, the short-circuiting path just traced around the winding of relay 7 and which includes the asymmetrical unit 21 and normal contact 16, conductor 3 winding of relay 8, conductor 2, controller contact 5, and to the negative terminal of battery 4. Hence, as long as the controller contacts 5 and 6 remain in the normal position, the winding of the relay 7 is short-circuited by the path including the asymmetrical unit 21, and the winding of the relay 8 receives current over the circuit that includes this same short-circuiting path. That is to say, although the position of the armatures of polar relay 7 agree with the polarity of the current supplied to the conductors 2 and 3, the winding of that relay is shortcircuited. It is clear, therefore, that the battery 4 is required to have a voltage only great enough to overcome the resistance of the winding of the relay 8.

Polar relay 7 in its normal position completes a shunt or short-ci-rcuiti-ng pa h for the winding of the relay 8 which path extends from the conductor 3 over wire 19, polar armature 18, normal contact 16, terminal 14 of rectifier 9, asymmetrical unit 22, terminal 11, and wire 13 to the conductor 2. The direction of the flow of current of normal polarity is such, however, that the asymmetric unit 22' in its high resistance direction substantially blocks all flow of current through the short-circui-ting path, and the energization of relay 8 is unaifected by it at this time.

When the controller contacts 5 and 6 are moved to the dotted line position and the current supplied to the conductors 2 and 3 is reversed in polarity, the asymmetrical unit 22 in the shortcircuiting path around the winding 8 becomes effective in its low resistance direction, and hence the current is shunted away from the winding of relay 8 and that relay is deenergized. The previously traced short-circuiting path around the winding of the polar relay 7, and which includes the asymmetric unit 21 is now no longer eiiective to pass current around the relay '2 due to the high resistance direction of asymmetric unit 21, and the polar relay 7 is energized.

circuit for energizing the polar relay 7 includes the positive terminal of battery 4, controller contact 5, conductor wire 13, terminal 11, asymmetrical unit 22 in its low resistance direction, terminal 14, normal contact 16, polar armature 18, wire 19, winding of relay 7, conductor 3, and controller contact 6 to the negative terminal of battery 4. Energizing the'polar relay 7 with current of reverse polarity causes its polar armatures l8 and 20 to be shifted to the corresponding reverse positions, that is, to the right-hand positions in the drawing. It is to be noted that the winding of the polar relay 7 only is in circuit to receive current from the conductors 2 3 subsequent to the reversal of the controller contacts 5 and 6, the winding of relay 8 being short-cir-- cuited at this time. Although the circuit for energizing the polar relay 7 with current of r verse polarity is opened as soon as the polar armature 18 moves out of engagement with the normal contact 16, the armatures l8 and 20 are fully reversed due to the well known fact that when energy is applied to a polar relay to reverse its armatures, the armatures go all the way over to the opposite position, ifthe applied energy is suflicient to start he armatures away from the position they previously occupied; Relay 8 being short-ci'cuited during the time the polar relay 7 is energized, the voltage required of the cattery 4 is only that necessary to energize the one relay.

The shifting of the polar armature 18 from engagement with the normal contact 16 into engagement with the reverse contact 17 opens the above described short-circuiting paths associated wit. the windings of th polar relay 7 and the neut relay 3, and completes two other shortcircuiting paths for the windings of these relays.

short-circuiting path for the winding of relay 7 now includes wire 19 extending from conductor 3 armature 18, reverse contact 17, terminal l5, asymmetric unit 23 of rectifier 9, terminal 1G, wire 12 to conductor 3. The shunt path around the winding of relay 8 now extends from the conductor 2 over wire 13, terminal 11, asymmetric unit 2 of rectifier 9, terminal 15, contact 17, ari store 18, and wire 19 to the conductor 3 The asymmetrical unit 23 is effective in its low resistance direction to pass current of reverse polarity, but the asymmetrical unit 24 in its high resistance direction substantially blocks the now of current or" reverse pola hence the winding of the relay 7 is hort-circuited, but the winding or" the relay 8 is not. Relay 8 is thus now energized by current from the battery 4 over a circuit th t in ludes the following elements: positive to ial of battery 4, controller contact 5, conduct r 2 inding of relay 8, conductor 3, wire 18, contact 17, terminal 15, asymf rectifier 9, terminal 10, wire 12, conductor .fi, and controller contact 6 to the negative tel al battery 4.

It is clear from the foregoing descli upon changing the polarity of the current supplied to the conductors 2 and 3 from that of normal polarity to that of reverse polarity the short-circuiting path for the polar relay 7 becomes ineffective to pass current around that relay, and the short-circuiting path for the windof the relay 8 becomes effective to shunt that relay with the result that the polar relay 7 becomes energized to shift its armatures to the reverse position, and the neutral relay 8 becomes deenergized. Immediately following the shifting of the armature 18 of th polar relay from the normal position to the reverse position two additional short-circuiting paths are completed, one

metrical unit of which. is efiective to pass the current of reverse polarity around the winding of the polar relay 7, and the relay 7 is deenergized, but the other is ineffective to pass current of reverse polarity around the winding of relay 8 relay 8 is reenergized. It is tobe noted that in this operationof the relays 7 and 8 in response to a reversal of the polarity of the current only the winding of one relay at a time is in circuit.

Restoring the controller contacts 5 and 6 from the reverse position to their normal position, and hence changing the current from reverse polarity to that of normal polarity, the winding of the relay 8 is short-circuited and that relay is at once deenergized; the short-circuiting path including th asymmetrical unit 24 being effective to pass current of normal polarity around relay 8. The short-circuiting path including the asymmetrical unit 23 is now no longer effective to pass current around the winding of the polar relay 7, and hence that relay is now energized with current of normal polarity. This circuit for energizing relay 7 extends from the positive terminal of battery l over controller. contact 6, conductor 3, winding of relay 7, conductor 3, wire 19, armature 18, reverse contact 17', terminal 15, asymmetrical unit 24 of rectifier 9, terminal 11, wire 13, conductor 2, and controller contact 5 to the negative terminal of battery 4. It follows that changing the current from reverse polarity to normal polarity deenergizes the relay 8 and energizes the polar relay 7. Energizing the relay '7 with current of normal polarity shifts its armature 18 from engagement with the reverse contact 17 over into engagement with the normal contact 16. Although the circuit for energizing the relay 7 is opened as soon as the armature 18 leaves the reverse contact 17, the armature 18 is moved to its full normal position. Armature 18 upon being restored to its normal position, com pletes the two normal short-circuiting paths, one of which includes the asymmetrical unit 21, and the other of which includes the asymmetrical unit 22 as fully described hereinbefore. Consequently, the polar relay 7 is now deenergized and the neutral relay 8 reenergized. Again it is to be noted that during the operation of the relays 7 and 8 subsequent to changing the polarity of the current from reverse polarity to that of normal polarity only the winding of one relay is in circuit at a time, the other being short-circuited by the associated short-circuiting path.

A control circuit such as here disclosed provides simultaneous control of two relays, although the power required from the current source at any one time will be that required to operate one relay only. The neutral relay being energized over a circuit which includes a polar contact of the polar relay, the neutral relay will be on short circuit and so will not be picked up unless the position of the polar armature agrees with the polarity of the current supplied by the control circuit, and hence agreement between the polar relay and the polarity of the current will be checked at each operation.

Although we have herein shown and described only one form of apparatus embodying our invention, it is understood that various changes and modifications may be made therein within the scope of the appended claims without departing from the spirit and scope of our invention.

Having thus described our invention, what we claim is:

1. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay having a winding arranged to receive current from said conductors, a first means including an asymmetrical unit and a normal contact of the polar relay for short-circuit ing the winding of the polar relay when current of normal polarity is supplied to said conductors, and a second means including an asymmetrical unit and a reverse contact of the polar relay for short-circuiting the winding of the polar relay when current or" reverse polarity is supplied to the conductors whereby the polar relay receives current from the conductors only when the polarity of the current disagrees with the position of said relay.

2. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay having a winding arranged to receive current from said conductors, a first means including a normal contact of the polar relay for short-circuiting the winding of the polar relay when current of normal polarity is supplied to said conductors, a second means including a reverse contact of the polar relay for short-circuiting th winding of the polar relay when current of reverse polarity is supplied to the conductors, and means for rendering said first and second means ineiTective when disagreement exists between the position of the relay and the polarity of the current whereby said relay receives current from the conductors at each reversal of the current.

3. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay having a winding arranged to receive current from said conductors, a first means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt current of normal polarity around the winding of said polar relay, and a second means including an asymmetrical unit and a reverse contact of the polar relay and arranged to shunt cur rent of reverse polarity around the winding of said polar relay whereby the polar relay receives current from the conductors only when the polarity of the current disagrees with the position of said relay.

4. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay having a winding arranged to receive current from said conductors, a first asymmetrical unit effective in the normal posi tion of said polar relay to shunt current of normal polarity around the winding of said relay, and a second asymmetrical unit effective in the reverse position of said polar relay to shunt current of reverse polarity around the winding of said relay whereby the relay is energized only when the polarity of the current disagrees with the position of said relay.

5. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay and a neutral relay each hav ing a winding arranged to receive current from said conductors, a first means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt current of normal polarity around the winding of the polar relay, a second means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt current of reverse polarity around the winding of the neutral relay, a third means including an asymmetrical unit and a reverse contact of the polar relay and arranged to shunt current of reverse polarity around the winding of the polar relay, and a fourth means ineluding an asymmetrical unit and a reverse contact of the polar relay and arranged to shunt current of normal polarity around the winding of the neutral relay.

6. In combination, a pair of conductors, a source of current, means for reversibly connecting said source with said conductors to supply current of normal or reverse polarity to the conductors, a polar relay and a neutral relay each having a winding arranged to receive current from said conductors, a first means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt current of normal polarity around the winding of the polar relay, and a second means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt current of reverse polarity around the winding of the neutral relay.

'7. In combination, a pair of conductors, a source of current, means for selectively supplying current of normal or reverse polarity to said conductors from the source, a polar relay and a neutral relay each having its Winding connected with said conductors, a first means including an asymmetrical unit and a normal contact of the polar relay and arranged to shunt crurent of reverse polarity around the winding of the neutral relay, and a second means including an asymmetrical unit and a reverse contact of the polar relay and arranged to shunt current of normal polarity around the winding of the neutral relay whereby the neutral relay is energized subsequent to a reversal in the polarity of the current supplied to the conductors only if the position of the polar relay is brought into agreement with the polarity of the current.

8. In combination, a pair of conductors, a source of current, means for selectively supplying current of normal or reverse polarity to said conductors from the source, a polar relay and a neutral relay each having its winding connected with said conductors, means governed by the normal position of the polar relay for shunting current of r verse polarity around the Winding of the neutral relay, and means governed by the re verse position of the polar relay for shunti current of normal polarity around the winding of the neutral relay whereby the neutral relay is energized subsequent to a reversal in the polarity of the current supplied to said conductors only if the position of the polar relay is first brought into agreement with the polarity of the current.

9. In combination, a pair of line Wires, means for reversibly supplying current to line wires, a pair of relays comprising a polar relay and a neutral relay having their windings serially connected with the line wires, a first means made efiective by the normal position of the polar relay to shunt current of normal polarity around the winding of the polar relay, a second means made effective by the reverse position of the polar relay to shunt current of reverse polarity around the winding of the polar relay, a third means effective to shunt current around the winding of the neutral relay in response to disagreement hetween the position of the polar relay and the polarity of the line current, whereby the neutral relay only is normally in circuit with the line wires and the polar relay only is in circuit at a reversal of the polarity of the line current.

1o. In combination, a pair of line wires, means for reversibly supplying current to said line wires, a polar relay and a neutral relay having their windings arranged serially with said conductors, a full wave rectifier, a first means including a. normal contact of the polar relay to render the rectifier effective to pass current of normal polarity around the winding of the polar relay and to pass current of reverse polarity around the winding of the neutral relay, and a second means including a reverse contact of the polar relay to render the rectifier effective to pass current of reverse polarity around the winding of the polor relay and to pass current of normal polarity around the winding of the neutral relay whereby only the winding of the neutral relay or the winding of the polar relay is in circuit with said conductors at a time.

ll. In combination, a pair of conductors, a source of current, means for supplying from said source to said conductors current of either normal or reverse polarity to establish diiTerent control conditions, a polar relay and a neutral relay having their windings serially connected with conductors, and means effective in response to a reversal of the polarity of the current to energize the windings of said relays successively vhereby operation of the two relays to the position corresponding to the established condition is effected Toy a current source having sufficient voltage to energize a single relay only.

PAUL H. CRAGO. MILLARD ROSENFELD. 

